Azzurro and Epistar say they have achieved GaN-on-Si based LEDs utilizing Epistar's high-brightness LED structures and Azzurro's patented technology for 150mm GaN-on-Si. The joint project, completed in four months, transferred Epistar's existing LED structures built on sapphire to the GaN-on-Si material system. The companies characterized the achievement as "one step further towards implementation in mass production."
Using templates with strain engineering, Azzurro's technology enables epitaxy engineers to quickly transfer LED structures to GaN-on-Si, the company says. A patented and proprietary buffer stress management enables better homogeneity (<4 nm wavelength homogeneity) for LED epi wafers, helping to reduce binning and increase yield.
"We are very excited about the outcome of this joined exercise which has exceeded all expectations regarding speed and cost of migration. The success helps us to utilize GaN-on-Si which is a game changer for the industry," stated Epistar chairman Lee Biing-Jye. "The technology to enable the LED industry to tap into the advantages of the volume, cost-effectiveness, and maturity of silicon foundries is ready with our strain-engineered templates," added by Erwin Wolf, CEO of Azzurro.
The promise of GaN-on-Si is to match the performance of sapphire-based devices, but using silicon equipment long commercially proven in the semiconductor industry to scale up operations, boost yields, and ultimately lower costs. In fact, the semiconductor industry is progressing toward consensus on building-block standards for automating LED production on 6-in [150mm] wafers. Toshiba is planning to ramp LED production using GaN-on-Si 200mm substrates by year's end, through a collaboration with Bridgelux.
imec, meanwhile, has its own research program to develop GaN-on-Si power devices on 200mm wafers. Last year it produced successful wafers, and has also developed the prerequisite fabrication process with standard CMOS processes and tools. (Days ago ON Semiconductor joined that imec program, as it builds a GaN processing line in Belgium.)
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